Liquid contact tilt inertial switch with movable metallic conductive means responsive to acceleration and deceleration forces

ABSTRACT

Upper and lower chambers are connected by a restricted passageway and contain three electrical contacts and a conductive fluid respectively. A ball disposed in the upper chamber and biased by a magnet to close the passageway connects one contact with another when the vehicle undergoes excessive deceleration or when it is tilted on its side. Fluid flows from the lower into the upper chamber to connect the one contact with the third when the vehicle is inverted.

United States Patent 11 1 1111 3,836,739 Endo 1 1 Sept. 17, 1974 15 LIQUID CONTACT TILT INERTIAL 2,912,534 11/1959 Rowell et al ZOO/61.47 SWITCH WITH MOVABLE METALLIC 3,351,347 11/1967 Smith et a1 ZOO/61.47 X CONDUCTIVE MEANS RESPONSIVE T0 25 1:; ACCELERATION AND DECELERATION 3,789,170 1 1974 Ferrario ZOO/61.47

FORCES Inventor: Takuya Endo, Yokohama, Japan Assignee: Nissan Motor Company, Limited,

Yokohama City, Japan Filed: Nov. 12, 1973 Appl. No; 414,942

Foreign Application Priority Data Nov. 14, 1972 Japan 47-13034] U.S. Cl.... ZOO/61.47, ZOO/61.45 M, ZOO/61.52, 200/223 Int. Cl. H01h 35/02, HOlh 29/10 Field of Search. ZOO/61.45 R, 61.45 M, 61.47, 200/61.52, 187, 188, 220, 221, 223, 228,

References Cited UNITED STATES PATENTS 6/1959 Rubinstein ZOO/61.45 M

Primary Examiner.lames R. Scott Attorney, Agent, or FirmRobert E. Burns; Emmanuel J. Lobato; Bruce L. Adams [5 7] ABSTRACT Upper and lower chambers are connected by a restricted passageway and contain three electrical contacts and a conductive fluid respectively. A ball disposed in the upper chamber and biased by a magnet to close the passageway connects one contact with another when the vehicle undergoes excessive deceleration or when it is tilted on its side. Fluid flows from the lower into the upper chamber to connect the one contact with the third when the vehicle is inverted.

1 Claim, 4 Drawing Figures LIQUID CONTACT TILT INERTIAL SWITCH WITH MOVABLE METALLIC CONDUCTIVE MEANS RESPONSIVE TO ACCELERATION AND DECELERATION FORCES The present invention relates to an accident detecting switch for a vehicle.

So-called accident detecting switches of the prior art are utilized to cut off the whole electric system and/or fuel supply system of a vehicle to prevent burning or exploding of the vehicle during the collision. A typical accident detecting switche generally comprises a deceleration switch mounted along the longitudinal axis of the vehicle to respond to an applied deceleration in one direction or within a given angular range. However, with this type of accident detecting switch it is impossible to discriminate upset of the vehicle from lateral turning of the vehicle. Thus, initiation of proper safety devices has been difficult with prior art accident detecting switches.

It is accordingly an object of the present invention to provide an accident detecting switch for a vehicle which is capable of discriminating upset of the vehicle from lateral turning of the vehicle.

Other objects, features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a cross sectional view of an embodiment of an accident detecting switch according to the present invention;

FIG. 2 is a cross sectional view of the switch when decelerated in a horizontal or lateral direction;

FIG. 3 is a cross sectional view of the switch when the vehicle is turned on its side; and

FIG. 4 is a cross sectional view of the switch when the vehicle is upset.

Referring to the accompanying drawing, there is shown an accident detecting switch according to the present invention, which includes first and second electrically non-conductive casings 12 and 14 respectively which are connected together by suitable means, and define therein first and second chambers 16 and 18 respectively connected by a restricted passageway 20. The chamber 18 normally contains an electrically conductive fluid such as mercury which flows into the chamber 16 when the vehicle is tilted or upset. In the present embodiment, the chambers 16 and 18 are spherical.

A first curved contact 22 is suitably fixed to the inner wall of the chamber 16 of the casing 14 about the opening of the passageway 20. An annular contact 26 is fixed to the inner wall of the chamber 16. A second curved contact 28 is fixed to the inner wall of the chamber 16 opposite to the contact 22. An electrically conductive ball 30 is movable within the chamber 16 but is normally biased by a magnet 32 to the position illustrated in FIG. 1 to block the passageway 20. Preferably, the contact 22 is formed with a tapered profile around the passageway for properly positioning the ball 30. The magnet 32 is in contact with the contact 22 and surrounds the passageway 20 as shown.

The contacts 26 and 28 are disposed in different parallel planes, such that the ball cannot bridge the space therebetween. The contacts 22 and 26 are spaced apart such that the ball 30 will bridge the space therebetween when the vehicle is subjected to an acceleration greater than a predetermined absolute magnitude (see FIG. 2).

The conductive liquid normally disposed in the chamber 18 has a volume less than half that of the chamber 18 so that the liquid will not enter the passageway 20 if the vehicle is tilted on its side (see FIG. 3), but it will flow into the chamber 16 and bridge the space between the contacts 26 and 28 upon upset of the vehicle (see FIG. 4). The ball 30 will connect the contacts 22 and 26 if the vehicle is tilted within a predetermined range from its upright position.

In case of a vehicle collision whereby the vehicle is accelerated or decelerated greater than the predetermined magnitude as shown in FIG. 2, the inertia of the ball 30 will cause it to move out of the influence of the magnetic field of the magnet 32 to connect the contacts 22 and 26. In case of a vehicle accident whereby the vehicle is tilted, the impact resulting will cause the ball 30 to move out of the influence of magnetic field to connect the contacts 22 and 26, but the liquid is still disposed in the chamber 18 and will not flow into the chamber 16. In both cases the contacts 22 and 26 are connected temporarily. The contact 26 may be connected to ground and the contact 22 to a circuit including a latching relay so that an electrical signal is produced at an output terminal thereof when the contacts 22 and 24 are connected.

In case of a vehicle accident whereby the vehicle is upset beyond the predetermined angular range as shown in FIG. 4, the impact resulting will cause the ball 30 to move out of the influence of the magnetic field to open the passageway 20. Thus, due to the gravity, the conductive fluid will flow into the chamber 16 through the restricted passageway 20 and fill the space between the contacts 26 and 28 to connect them. The contact 28 may be connected to an electric circuit so that another electric signal, upon upset of the vehicle, is produced at an output terminal thereof.

It will now be appreciated from the foregoing description that these two electric signals can be used for actuation of proper safety device initiation means corresponding to the respective accident conditions. The signal produced by contact of the contacts 22 and 26 may be used as an initiation signal for cutting off the ignition circuit, application of the brakes and inflation of an air bag mounted in the vehicle. The other signal may be used as an initiation signal for cutting off the ignition circuit and the fuel supply system mounted in the vehicle.

What is claimed is:

1. An accident detecting switch for a vehicle comprising: an electrically conductive ball; a normally vertical dielectric casing having an upper chamber and a lower reservoir joined by a restricted passageway, said upper chamber including said movable spherical contact member; a first electrical contact having an aperture at the bottom thereof communicating with the passageway; a second electrical contact; said first and second electrical contacts being disposed in said upper chamber in a spaced relationship; a magnet to attract said ball to said aperture to block said passageway and to maintain said ball separated from said second electrical contact; said ball being movable against the action of said magnet into contact with said first and second electrical contacts when an applied acceleration in any direction within a given plane exceeds a predetermined magnitude; a third electrical contact disposed in said upper chamber; and an electrically conductive fluid disposed in said lower reservoir, said fluid being adapted to flow into said upper chamber and into contact with said second and third electrical contacts sageway opened. 

1. An accident detecting switch for a vehicle comprising: an electrically conductive ball; a normally vertical dielectric casing having an upper chamber and a lower reservoir joined by a restricted passageway, said upper chamber including said movable spherical contact member; a first electrical contact having an aperture at the bottom thereof communicating with the passageway; a second electrical contact; said first and second electrical contacts being disposed in said upper chamber in a spaced relationship; a magnet to attract said ball to said aperture to block said passageway and to maintain said ball separated from said second electrical contact; said ball being movable against the action of said magnet into contact with said first and second electrical contacts when an applied acceleration in any direction within a given plane exceeds a predetermined magnitude; a third electrical contact disposed in said upper chamber; and an electrically conductive fluid disposed in said lower reservoir, said fluid being adapted to flow into said upper chamber and into contact with said second and third electrical contacts upon the upset of said dielectric casing with said passageway opened. 